Website down "cannot connect to server"

I feel like I’m taking crazy pills! My WordPress site has stopped loading in any browser, the message says that it is due to lack of server response, but our IT person here checked our system and said everything is operating normally.

Our personalized web admin login page is also not loading, and the primary WordPress login page it is not recognizing my original login.

Help a girl out! Why would our website inexplicably go down?